a(n) = 5*(10^(2*n+1)-1)/9 + 3*10^n.

A332158

a(n) = 5*(10^(2*n+1)-1)/9 + 3*10^n.

Terms

    a(0) =8a(1) =585a(2) =55855a(3) =5558555a(4) =555585555a(5) =55555855555

External references